Redundant control circuit for hot melt adhesive hose assembly heater circuits and temperature sensors

ABSTRACT

A hot melt adhesive hose assembly has a redundant control circuit fixedly mounted thereon which comprises a pair of heater circuits for heating a hot melt adhesive hose assembly to a predetermined temperature level, and a pair of temperature sensors which are used to sense the temperature of the hot melt adhesive hose assembly wherein the sensed temperature level will be used to control energization of the heater circuits in order to maintain the desired temperature level. A first one of the heater circuits is initially electrically connected to the hot melt adhesive hose assembly electrical circuitry, and in a similar manner, a first one of the temperature sensors is likewise electrically connected to the hot melt adhesive hose assembly electrical circuitry. Should a failure occur within the first one of the heater circuits, or within a first one of the temperature sensors, electrical switch mechanisms are activated so as to effectively remove the first, failed heater circuit or the first failed temperature sensor from the hot melt adhesive hose assembly electrical circuitry, and substantially simultaneously therewith, electrically connect the second one of the heater circuits or the second one of the temperature sensors to the hot melt adhesive hose assembly electrical circuitry. The hot melt adhesive hose assembly, with its redundant control circuit comprising the pair of heater circuits and the pair of temperature sensors, thus comprises a self-contained, stand-alone, independent operative component that can be utilized in conjunction with any hot melt adhesive supply unit (ASU).

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a Continuation-in-Part of U.S. patentapplication Ser. No. 11/123,028 which is entitled REDUNDANT CONTROLCIRCUIT FOR HOT MELT ADHESIVE HOSE ASSEMBLY HEATER CIRCUITS ANDTEMPERATURE SENSORS, and which was filed on May 6, 2005 in the name ofDaniel D. Bourget et al. This patent application is also related to U.S.patent application Ser. No. 11/123,053 which is entitled HOT MELTADHESIVE HOSE ASSEMBLY HAVING REDUNDANT COMPONENTS, and which was alsofiled on May 6, 2005 in the name of Daniel D. Bourget et al., and isalso related to U.S. patent application Ser. No. ______ which isentitled HOT MELT ADHESIVE HOSE ASSEMBLY HAVING REDUNDANT COMPONENTS,and which was filed on ______ in the name of Daniel D. Bourget et al.

FIELD OF THE INVENTION

The present invention relates generally to hot melt adhesive dispensingsystems, and more particularly to a new and improved redundant controlcircuit, for use in connection with a hot melt adhesive hose assembly,which effectively has redundant components inherently incorporatedtherein, such as, for example, redundant hot melt adhesive heatercircuits, and redundant hot melt adhesive temperature sensors, as wellas suitable switching mechanisms, whereby the hot melt adhesive hoseassembly, including the heater circuits, the temperature sensors, andthe switching mechanisms, effectively comprises a stand-alone,self-contained, or independent operative component that can be utilizedin conjunction with any adhesive supply unit (ASU) and its temperaturecontroller. Accordingly, should a failure occur within one of the hotmelt adhesive heater circuits, or within one of the hot melt adhesivetemperature sensors, the switching mechanisms may be suitably actuatedso as to effectively withdraw the failed hot melt adhesive heatercircuit, or the failed hot melt adhesive temperature sensor, from itsoperative or functional disposition within the electrical circuitry, andto substantially simultaneously therewith insert the backup or redundanthot melt adhesive heater circuit, or the backup or redundant hot meltadhesive temperature sensor, into the control circuitry whereby the hotmelt adhesive hose assembly does not need to be replaced immediately butcan be subsequently replaced in accordance with, for example, normalscheduled maintenance procedures, the hot melt adhesive dispensingproduction line does not need to be shut down for repairs wherebyextensive downtime to replace the failed hot melt adhesive hose assemblyis effectively able to be avoided, and the hot melt adhesive dispensingproduction line can continue to operate without any production downtime.

BACKGROUND OF THE INVENTION

In connection with hot melt adhesive dispensing systems, failures cangenerally occur within two different categories, that is, mechanicalfailures due to wear, or electrical failures due to electricalmalfunctions. More particularly, in connection with the different typesof electrical failures that can be experienced, electrical failures canoccur, such as, for example, either within the heater circuit which isused to maintain the hot melt adhesive material, that is flowing throughthe hot melt adhesive hose assembly, at a predetermined temperaturelevel, or within the temperature sensor which is operatively orthermally associated with the hot melt adhesive hose assembly in orderto effectively detect the temperature level of the hot melt adhesivematerial, which is flowing through the hot melt adhesive hose assembly,and which effectively controls the heater circuit, through means of theadhesive supply unit (ASU) and its temperature controller, so as toensure that the desired temperature level of the hot melt adhesivematerial, which is flowing through the hot melt adhesive hose assembly,is in fact maintained. Maintenance of the proper or desired temperaturelevel of the hot melt adhesive material, which is flowing through thehot melt adhesive hose assembly, is therefore of course critical inorder to ensure that the hot melt adhesive material will have the properviscosity characteristics so as to be properly dispensed and thereforeprovide the desired adhesive properties once the hot melt adhesivematerial is in fact deposited onto a particular substrate. In eithercase, that is, whether a failure is experienced in connection with theheater circuit, or in connection with the temperature sensor, suchfailures typically cause the hot melt adhesive dispensing productionline to be shut down for extended periods of time, in order to implementthe repair or replacement of the failed components, whereby valuableproduction time is lost.

A hot melt adhesive dispensing apparatus employing redundant temperaturesensing devices is disclosed within United States Patent ApplicationPublication 2005/0092736 which was published on May 5, 2005 in the nameof Raterman et al. More particularly, as can be appreciated from FIG. 1,which substantially corresponds to FIG. 1 of the aforenoted patentpublication, the adhesive dispensing apparatus of Raterman et al. isgenerally indicated by the reference character 10 and is seen tocomprise an adhesive dispensing gun 20 for depositing adhesive material22 onto a substrate 24. The adhesive dispensing gun 20 is mounted upon amanifold 18, and a supply tank or adhesive supply unit (ASU) 16,containing a supply of the adhesive material 22, is fluidicallyconnected to the manifold 18 by means of a hose assembly 12 and a pump14, with an inlet end 42 of the hose assembly 12 being fixedly connectedto the pump 14 while an outlet end 44 of the hose assembly 12 is fixedlyconnected to the manifold 18. The hose assembly 12 is also provided witha wire harness 28 which is connected to a controller 32, through meansof an electrical connector 80, which is mounted upon the supply tank oradhesive supply unit (ASU) 16, and the supply tank or adhesive supplyunit (ASU) 16 also includes a heater 26 which is selectively controlledso as to maintain the adhesive material 22, disposed within the supplytank or adhesive supply unit (ASU) 16, within a predeterminedtemperature range.

The hose assembly 12 further comprises a heating element and a pair oftemperature sensing devices, not illustrated within FIG. 1 but fullydisclosed within the aforenoted patent publication to Raterman et al.,wherein the pair of temperature sensing devices sense the temperature ofthe adhesive material flowing through the hose assembly 12, and whereinfurther, the pair of temperature sensing devices are alternativelyelectrically connected to the controller 32 so as to in fact monitor thetemperature of the adhesive material 22 flowing through the hoseassembly 12. The controller 32 monitors the temperature from one or bothof the two temperature sensing devices and controls the operation of theheating element, based upon the readings from the particular one or bothof the two temperature sensing devices so as to maintain the hot meltadhesive material at a desired temperature level. If one of the twotemperature sensing devices is found to be malfunctioning or failing,then that particular one of the two temperature sensing devices isdeactivated and the other one of the two temperature sensing devices isactivated or remains active so as to function within the heater controlsystem. The switch-over between the two temperature sensing devices maybe either accomplished manually, such as, for example, by hard wiringthe temperature sensing devices to the controller input, orautomatically through means of a suitable relay or other controloperation or circuit incorporated within the controller 32.

While the hot melt adhesive dispensing apparatus employing the redundanttemperature sensing devices, as disclosed within the aforenoted patentapplication publication to Raterman et al., is operationallysatisfactory, several operational drawbacks of the apparatus are alsoapparent from the disclosure. For example, it is initially noted thatwhile redundant temperature sensing devices are disclosed, there is nodisclosure of redundant heating elements. This is critically importantin that, as has been noted hereinbefore, electrical failures can occurwithin the heater circuit which is used to maintain the hot meltadhesive material, that is flowing through the hot melt adhesive hoseassembly, at a predetermined temperature level, as well as within thetemperature sensor which detects the temperature level of the hot meltadhesive material that is flowing through the hot melt adhesive hoseassembly. Furthermore, and just as importantly, if not more importantly,as has also been noted hereinbefore, the redundant temperature sensingdevices of the Raterman et al. apparatus or system are intimatelyconnected to the temperature controller 32 that forms an integral partof the adhesive supply unit (ASU) 16. Accordingly, the hose assembly 12is intimately dependent upon, and can only be used in conjunction with,the particular temperature controller 32 and the particular adhesivesupply unit (ASU) 16. Viewed from a slightly different perspective orpoint of view, the hose assembly 12 of Raterman et al. does not comprisea stand-alone, self-contained, or independent operative component thatcan readily be used in conjunction with any adhesive supply unit (ASU),or viewed in a still similar manner, the hose assembly 12 of Raterman etal. cannot be disconnected from a particular adhesive supply unit (ASU)and readily operatively connected to another adhesive supply unit (ASU).

A need therefore exists in the art for a new and improved redundantcontrol circuit, for use in conjunction with a hot melt adhesive hoseassembly, wherein redundant electrical components could effectively beincorporated such that if a failure occurs within a particularelectrical component, the failed electrical component could effectivelybe removed from its operative or functional disposition within theelectrical circuitry, and the other electrical component couldeffectively be operatively or functionally incorporated into theelectrical circuitry. In this manner, the hot melt adhesive dispensingproduction line would not need to be shut down for extended periods oftime, in order to implement the replacement of the failed hot meltadhesive hose assembly, whereby valuable production time would not belost. In addition, a need exists in the art for a new and improvedredundant control circuit, for use in conjunction with hot melt adhesivehose assembly, wherein the hot melt adhesive hose assembly, having theheater circuits, the temperature sensors, and the switching mechanismsincorporated therein, effectively comprises a stand-alone,self-contained, or independent operative component which can be utilizedin conjunction with any adhesive supply unit (ASU) and its temperaturecontroller.

SUMMARY OF THE INVENTION

The foregoing and other objectives are achieved in accordance with theteachings and principles of the present invention through the provisionof a new and improved redundant control circuit which comprises a pairof heater circuits which are adapted to be wrapped around the externalperipheral surface of a hot melt adhesive hose assembly core, a pair oftemperature sensors which are also adapted to be disposed in contactwith the external peripheral surface of the hose core, and a pluralityof switching mechanisms which are also an integral component part of theredundant control circuit and the hot melt adhesive hose assembly.Accordingly, the new and improved hot melt adhesive hose assembly,including the heater circuits, the temperature sensors, and theplurality of switching mechanisms, effectively comprises aself-contained, stand-alone, or independent operative component that canbe utilized in conjunction with any adhesive supply unit (ASU) and itstemperature controller. A first one of the heater circuits wouldinitially be electrically connected to the hot melt adhesive hoseassembly electrical circuitry, and in a similar manner, a first one ofthe temperature sensors would likewise be electrically connected to thehot melt adhesive hose assembly electrical circuitry.

Subsequently, should a failure occur within the first one of the heatercircuits, then one or more of the electrical switching mechanisms wouldbe activated so as to effectively remove the first, failed heatercircuit from the hot melt adhesive hose assembly electrical circuitry,and substantially simultaneously therewith, electrically connect thesecond one of the heater circuits into the hot melt adhesive hoseassembly electrical circuitry. Similar switching procedures would alsobe implemented in connection with the pair of temperature sensors shoulda failure occur within a first one of the temperature sensors initiallyincorporated within the hot melt adhesive hose assembly electricalcircuitry. In this manner, the hot melt adhesive hose assembly does notneed to be replaced immediately but can be subsequently replaced inaccordance with, for example, normal scheduled maintenance procedures,the hot melt adhesive dispensing production line does not need to beshut down for repairs whereby extensive downtime to replace the failedhot melt adhesive hose assembly is effectively able to be avoided, andthe hot melt adhesive dispensing production line can continue to operatewithout any production downtime.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other features and attendant advantages of the present inventionwill be more fully appreciated from the following detailed descriptionwhen considered in connection with the accompanying drawing wherein:

FIG. 1 is a perspective view of a conventional, PRIOR ART hot meltadhesive dispensing system wherein redundant temperature sensing devicesare operatively associated with the hot melt adhesive hose assembly; and

FIG. 2 comprises an electronic circuit diagram schematicallyillustrating the new and improved redundant control circuit, operativelyassociated with a hot melt adhesive hose assembly, and developed inaccordance with the principles and teachings of the present invention,and showing the cooperative parts thereof, wherein a pair of redundantheater circuits and a pair of redundant temperature sensors, along witha first pair of switching mechanisms operatively connected to the pairof redundant heater circuits, and a second pair of switching mechanismsoperatively connected to the pair of redundant temperature sensors, areoperatively incorporated within the new and improved electronic controlcircuit such that should a failure occur within a first one of the pairof redundant heater circuits, then the first pair of switchingmechanisms will be activated so as to effectively remove the first,failed heater circuit from the hot melt adhesive hose assemblyelectrical circuitry, and substantially simultaneously therewith,electrically connect the second one of the pair of redundant heatercircuits to the hot melt adhesive hose assembly electrical circuitry,while in a similar manner, should a failure occur within a first one ofthe pair of redundant temperature sensors, then the second pair ofswitching mechanisms will be activated so as to effectively remove thefirst, failed temperature sensor from the hot melt adhesive hoseassembly electrical circuitry, and substantially simultaneouslytherewith, electrically connect the second one of the pair of redundanttemperature sensors to the hot melt adhesive hose assembly electricalcircuitry, whereby immediate replacement of the failed heater circuit orfailed temperature sensor is no longer necessary and can be delayeduntil the implementation of normally scheduled maintenance procedures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, and more particularly to FIG. 2 thereof,the new and improved redundant control circuit, which has been developedin accordance with the principles and teachings of the present inventionand which shows the cooperative parts thereof, and which is adapted tobe operatively associated with a hot melt adhesive hose assembly, suchas, for example, that disclosed within the aforenoted copending UnitedStates patent application entitled HOT MELT ADHESIVE HOSE ASSEMBLYHAVING REDUNDANT COMPONENTS, which was filed on May 6, 2005, and whichhas been assigned Ser. No. 11/123,053, is disclosed and is generallyindicated by the reference character 10. As is well known in the hotmelt adhesive material dispensing art, hot melt adhesive material isnormally supplied to a hot melt adhesive hose assembly, not shown, froma hot melt adhesive supply unit (ASU), also not shown, in a heatedstate, and a heater circuit or heater assembly is conventionallyoperatively associated with the hot melt adhesive hose assembly in orderto maintain the hot melt adhesive material at a predeterminedtemperature level, while the same is being conducted through the hotmelt adhesive hose assembly, such that the hot melt adhesive materialwill have or exhibit the proper viscosity properties when the hot meltadhesive material is dispensed from the applicator end of the hot meltadhesive hose assembly.

In addition, a temperature sensor is likewise conventionally operativelyassociated with the hot melt adhesive hose assembly so as to effectivelydetect or sense the temperature level of the hot melt adhesive materialbeing conducted through the hot melt adhesive hose assembly, wherebysuch detected or sensed temperature level is effectively orappropriately used to control, through means of a suitable temperaturecontroller, the energization of the heater circuit or heater assembly soas to again ensure the fact that the hot melt adhesive material is beingheated to, and maintained at, the proper temperature level while thesame is being conducted through the hot melt adhesive hose assembly suchthat the hot melt adhesive material will have or exhibit the properviscosity properties when the hot melt adhesive material is dispensedfrom the applicator end of the hot melt adhesive hose assembly. As hasbeen noted hereinbefore, electrical failures can occur within hot meltadhesive material dispensing systems either within, for example, theheater circuit or heater assembly which is used to maintain the hot meltadhesive material, which is flowing through the hot melt adhesive hoseassembly, at a predetermined temperature level, or within thetemperature sensor which is operatively or thermally associated with thehot melt adhesive hose assembly in order to effectively detect thetemperature level of the hot melt adhesive material, which is flowingthrough the hot melt adhesive hose assembly, and to effectively control,through means of a suitable temperature controller, the energization ofthe heater circuit or heater assembly so as to effectively ensure thatthe desired temperature level of the hot melt adhesive material, whichis flowing through the hot melt adhesive hose assembly, is in factmaintained.

Maintenance of the proper or desired temperature level of the hot meltadhesive material is of course critical in order to ensure that the hotmelt adhesive material will be properly dispensed, and will provide thedesired adhesive properties, once the hot melt adhesive material is infact deposited onto a particular substrate. In either case, that is,whether a failure is experienced in connection with the heater circuitor heater assembly, or in connection with the temperature sensor, suchfailures typically cause the hot melt adhesive dispensing productionline to be shut down for extended periods of time, in order to implementthe replacement of the hot melt adhesive hose assembly, whereby valuableproduction time is lost. It has therefore been determined that it wouldbe desirable to effectively incorporate redundant heater circuits orheater assemblies, as well as redundant temperature sensors, into thehot melt adhesive hose assembly, and to provide a new and improvedredundant control circuit for effectively controlling the activation orenergization of the redundant heater circuits or heater assemblies, aswell as the redundant temperature sensors, such that if a failure occurswithin a particular one of the heater circuits or heater assemblies, orwithin a particular one of the temperature sensors, the failed heatercircuit or heater assembly, or the failed temperature sensor, couldreadily and immediately be effectively removed from its operative orfunctional disposition within the electrical circuitry, and the othercorresponding heater circuit or heater assembly, or temperature sensor,could readily and immediately be operatively or functionallyincorporated into the electrical circuitry. In this manner, the hot meltadhesive dispensing production line would not need to be shut down forextended periods of time, in order to implement the replacement of thefailed hot melt adhesive hose assembly, whereby valuable production timewould not be lost.

More particularly, then, it is seen that the new and improved redundantcontrol circuit 10, for achieving the aforenoted desirable results,comprises an electrical connector 12 which is part of a hot meltadhesive hose assembly and which is adapted to receive electrical powerfrom a suitable main power supply 14 which is operatively associatedwith an adhesive supply unit (ASU), not shown, a pair of heater circuitsor heater assemblies 16,18 which are electrically connected to theelectrical connector 12 by means of a first pair of primary power lines20,22, and a pair of temperature sensors 24,26 which are electricallyconnected to the electrical connector 12 by means of a second pair ofprimary power lines 28,30. It is noted that while each one of thetemperature sensors 24,26 may comprise, and has been designated in FIG.2 as a resistance temperature detector (RTD), each temperature sensor24,26 may alternatively comprise a thermistor, or a thermocouple. It isfurther seen that the opposite ends of the first heater circuit orheater assembly 16 are electrically connected to the first pair ofprimary power lines 20,22 by means of a first pair of switch mechanisms32,34 and a first pair of auxiliary connection lines 36,38, while theopposite ends of the second heater circuit or heater assembly 18 areelectrically connected to the first pair of primary power lines 20,22 bymeans of a second pair of switch mechanisms 40,42 and a second pair ofauxiliary connection lines 44,46.

Accordingly, it can readily be appreciated that when, for example, thefirst pair of switch mechanisms 32,34, operatively associated with thefirst heater circuit or first heater assembly 16, are both disposed attheir CLOSED positions, while the second pair of switch mechanisms40,42, operatively associated with the second heater circuit or secondheater assembly 18, are both disposed at their OPEN positions, the firstheater circuit or first heater assembly 16 will be electricallyconnected into the overall redundant control circuit 10 and will beelectrically connected to the electrical connector 12 so as to receiveelectrical power therefrom in order to heat the hot melt adhesive hoseassembly, not shown. Conversely, when, for example, the second pair ofswitch mechanisms 40,42, operatively associated with the second heatercircuit or second heater assembly 18, are both disposed at their CLOSEDpositions, while the first pair of switch mechanisms 32,34 operativelyassociated with the first heater circuit or first heater assembly 16,are both disposed at their OPEN positions, the second heater circuit orsecond heater assembly 18 will be electrically connected into theoverall redundant control circuit 10 and will be electrically connectedto the electrical connector 12 so as to receive electrical powertherefrom in order to heat the hot melt adhesive hose assembly, notshown.

Continuing further, it is similarly seen that the opposite ends of thefirst temperature sensor 24 are electrically connected to the secondpair of primary power lines 28,30 by means of a third pair ofsingle-throw, double-pole switch mechanisms 48,50 and a third pair ofauxiliary connection lines 52,54, while the opposite ends of the secondtemperature sensor 26 are electrically connected to the second pair ofprimary power lines 28,30 by means of the third pair of single-throw,double-pole switch mechanisms 48,50 and a fourth pair of auxiliaryconnection lines 56,58. It is more particularly seen that the firstsingle-throw, double-pole switch mechanism 48, of the third pair ofsingle-throw, double-pole switch mechanisms 48,50, actually comprises acommon terminal 60, a pair of alternatively selectable terminals 62, 64,and a switch member 66, while in a similar manner, the secondsingle-throw, double-pole switch mechanism 50, of the third pair ofsingle-throw, double-pole switch mechanisms 48,50, actually comprises acommon terminal 68, a pair of alternatively selectable terminals 70,72,and a switch member 74.

Accordingly, as was the case with the first and second heater circuitsor first and second heater assemblies 16,18, when, for example, thethird pair of switch mechanisms 48,50 are both disposed at their UPPERCLOSED positions at which the switch members 66,74 are disposed incontact with and electrically connected to the upper selectableterminals 62, 70, while simultaneously the switch members 66,74 aredisposed in OPEN states with respect to the lower selectable terminals64,72, then the first temperature sensor 24 will be electricallyconnected into the overall redundant control circuit 10 and will beelectrically connected to the electrical connector 12 so as to receiveelectrical power therefrom in order to monitor the temperature level ofthe hot melt adhesive hose assembly, not shown, so as to, in turn,effectively control the one of the first or second heater circuits, orfirst or second heater assemblies, 16,18 that is currently electricallyconnected into the overall circuit 10. Conversely, when, for example,the third pair of switch mechanisms 48,50 are both disposed at theirLOWER CLOSED positions at which the switch members 66,74 are disposed incontact with and electrically connected to the lower selectableterminals 64,72, while simultaneously the switch members 66,74 aredisposed in OPEN states with respect to the upper selectable terminals62,70, then the second temperature sensor 26 will be electricallyconnected into the overall redundant control circuit 10 and will beelectrically connected to the electrical connector 12 so as to receiveelectrical power therefrom in order to monitor the temperature level ofthe hot melt adhesive hose assembly, not shown, so as to, in turn,effectively control the one of the first or second heater circuits, orfirst or second heater assemblies, 16,18 that is currently electricallyconnected into the overall redundant control circuit 10.

The redundant control circuit 10 is seen to further comprise amicrocontroller 76 which is supplied with electrical power from asecondary power supply unit 78, and it is seen that the secondary powersupply unit 78 is electrically connected to the primary power lines20,22 through means of secondary power lines 80,82, and still further,the secondary power supply unit 78 is electrically connected to themicrocontroller 76 through means of a tertiary power line 84. A voltagebackup unit 86 is electrically connected to the secondary power supplyunit 78 by means of an electrical connection line 88, and the voltagebackup unit 86 is also electrically connected to a microcontrollersupervisor unit 90 by means of an electrical connection line 92 whilethe microcontroller supervisor unit 90 is, in turn, electricallyconnected to the microcontroller 76 by means of an electrical connectionline 94. Still further, an EEPROM type memory unit 96 is electricallyconnected to the microcontroller 76 by means of an electrical connectionline 98, and it is noted that the functions and operations of thesevarious electrical components, that is, for example, the microcontroller76, the voltage backup unit 86, the microcontroller supervisor unit 90,and the EEPROM type memory unit 96 will be discussed and explainedshortly hereafter.

Continuing further, in accordance with additional featurescharacteristic of the new and improved redundant control circuit 10developed in accordance with the principles and teachings of the presentinvention, a first current-voltage transformer or converter 100 iselectrically connected to or across the primary power line 20, while asecond current-voltage transformer or converter 102 is electricallyconnected to or across the primary power line 22. The current voltagetransformers or converters 100,102 are adapted to respectively detectthe current levels within the primary power lines 20,22, whichalternatively feed power to the first or second heater circuits, orfirst or second heater assemblies, 16,18 through means of the switchmechanisms 32,34, and 40, 42, and to convert such current levels tocorresponding voltage levels which are then fed into the microcontroller76 by means of data communication lines 104,106. A firstanalog-to-digital converter 108 is incorporated within themicrocontroller 76, and the data communication lines 104,106 areelectrically connected to the first analog-to-digital converter 108whereby the incoming analog voltage levels can be converted, by means ofthe first analog-to-digital converter 108, into digital voltage valueswhich can then of course be processed by means of the microcontroller76. In addition, a first voltage detector 110 is electrically connectedto, or across, the primary power lines 20, 22 so as to detect thevoltage level existing between the two primary power lines 20,22, andthe detected voltage level is fed into the first analog-to-digitalconverter 108 of the microcontroller 76 by means of a data communicationline 112 such that the incoming analog voltage level can be converted,by means of the first analog-to-digital converter 108, into a digitalvoltage value which can be processed by means of the microcontroller 76.In a similar manner, second and third temperature sensor-voltageconverters 114,116 are respectively electrically connected to, oracross, the third and fourth pairs of auxiliary connection lines 52,54,and 56,58, by means of connection lines 111,113 and 115,117, so as todetect or determine the voltage levels existing between the third andfourth pairs of auxiliary connection lines 52,54, and 56,58, and thedetected voltage levels are respectively fed into the firstanalog-to-digital converter 108 of the microcontroller 76 by means ofdata communication lines 118,120 such that the incoming analog voltagelevels can likewise be converted, by means of the firstanalog-to-digital converter 108, into digital voltage values which canbe processed by means of the microcontroller 76.

In connection with the operation of the new and improved redundantcontrol circuit 10 of the present invention, when the adhesive supplyunit (ASU), not shown, is activated, the main power supply 14operatively associated with the adhesive supply unit (ASU) applies ortransmits power to the electrical connector 12 whereby a direct current(DC) voltage will be generated and the microcontroller 76 is booted oractivated. The EEPROM type memory unit 96 stores various parameters andoperational profiles operatively associated with the differentcomponents comprising the electronic control circuit 10, such as, forexample, the various current, voltage, power values, duty cycles, andthe like, generated by, or operatively characteristic of, the heatercircuits or heater assemblies 16,18, and the temperature sensors 24,26,as conveyed to the microcontroller 76 by means of the aforenoted datacommunication lines 104,106,112,118,120. Accordingly, themicrocontroller 76 will retrieve the most current data stored within theEEPROM type memory unit 96, and will perform various system checkscomprising the current levels, voltage levels, power levels, the dutycycle, and the like.

In addition, the microcontroller 76 will activate particular ones of theswitch mechanisms 32,34,40,42,48,50, which are respectively connected tothe microcontroller 76 by means of signal lines 122,124,126,128,130,132,such that particular ones of the switch mechanisms 32,34,40,42,48,50will be moved to their CLOSED positions. In this manner, a particularone of the first or second heater circuits or heater assemblies 16,18,as well as a particular one of the first or second temperature sensors24,26, will effectively be incorporated into the operative systemcomprising the redundant control circuit 10. It is also noted that theredundant control circuit 10 further comprises a communication interface134 which is electrically connected to the microcontroller 76 by meansof a data communication line 136, and a status indication means 138which is electrically connected to the microcontroller 76 by means of adata communication line 140. The communication interface 134 maycomprise, for example, a computer keyboard, a display panel, and thelike, while the status indication means may comprise, for example, greenand red LEDs, indicator lights, and the like.

It is further noted that the voltage backup unit 86 serves severalfunctions, such as, for example, providing energy for a predeterminedtime period, such as, for example, several seconds, after the adhesivesupply unit (ASU) has, for example, initiated a shut-down of the firstor second heater circuits, or the first or second heater assemblies,16,18, in accordance with an end-of-cycle mode of operation wherein theresidual energy provided by means of the voltage backup unit 86 cannevertheless maintain the microcontroller supervisor 90 active so as to,for example, shut down the microcontroller in a controlled manner ormode. In a similar manner, the voltage backup unit 86 can provide energyduring those time periods within which the first or second heatercircuits, or the first or second heater assemblies, 16,18 are beingoperated in accordance with low duty cycles.

Still further, it is noted that in addition to the voltage detector 110being electrically connected to the microcontroller 76 by means of datacommunication line 112, the voltage detector 110 is also electricallyconnected to the microcontroller supervisor 90 by means of a datacommunication line 142. Accordingly, if, for example, the voltagedetector 110 detects a significantly low voltage level, or the loss ofvoltage, for a predetermined period of time, such as, for example,several seconds, then the voltage backup unit 86 can provide sufficientpower to enable the current operating system parameters to be storedwithin the EEPROM type memory unit 96, and for the microcontrollersupervisor 90 to again shut down the microcontroller 76 in a controlledmanner or mode. It is lastly noted that at all other times, themicrocontroller supervisor 90 serves to monitor the microcontroller 76in order to determine and verify the fact that the microcontroller 76 isoperating properly or within normal parameters.

It is to be noted that during normal hot melt adhesive dispensingoperations or procedures, or during normal hot melt adhesive applicationcycles, if, for example, the switch mechanisms 32,34 have beenpreviously moved to their CLOSED positions so as to electricallyincorporate or connect the first heater circuit or first heater assembly16 into the redundant control circuit 10, while the switch mechanisms40, 42 have been previously moved to their OPEN positions so as toelectrically disconnect or isolate the second heater circuit or secondheater assembly 18 from the redundant control circuit 10, and ifsubsequently, for example, a heater failure is detected as a result of,for example, a significant change in the heater current as detected bymeans of the current-voltage transformers or converters 100,102, and ascompared to, for example, the normal heater current profile data storedwithin the EEPROM type memory unit 96, then the microcontroller 76 willinitiate a switchover of the switch mechanisms, by means of suitablesignals transmitted over the signal lines 122,124,126,128, so as to moveswitch mechanisms 32,34 to their OPEN positions whereby the first heatercircuit or first heater assembly 16 will now be electricallydisconnected or isolated from the redundant control circuit 10, andsubstantially simultaneously therewith, to move the switch mechanisms40,42 to their CLOSED positions whereby the second heater circuit orsecond heater assembly 18 will now be electrically connected to orincorporated within the redundant control circuit 10. It is also to benoted that a heater failure can manifest itself in the form of a groundfault in connection with, for example, the first heater circuit or firstheater assembly 16 if the first heater circuit or first heater assembly16 is the heater circuit or heater assembly electrically connected to orincorporated within the redundant control circuit 10. In particular, notonly should the heater circuit or heater assembly current valuesdetected by means of the current-voltage converters or transformers100,102 effectively be in accordance with the normal heater currentprofile data stored within the EEPROM type memory unit 96, but thedetected values should also be the same within both of the primary powerlines 20,22. If this is not the case, the first heater circuit or firstheater assembly 16 may have a ground fault. Still yet further, if thecurrent values, detected within both of the primary power lines 20, 22,change suddenly, although the duty cycle remains constant, this mayindicate a defective heater circuit or heater assembly whereby aswitchover between the first and second heater circuits or first andsecond heater assemblies 16,18 would again be warranted.

It is lastly noted, in connection with the operations and connections ofthe first and second heater circuits or first and second heaterassemblies 16,18 within the redundant control circuit 10, that it may bedesirable to simultaneously activate all of the switch mechanisms32,34,40,42 to their CLOSED positions such that both of the first andsecond heater circuits or first and second heater assemblies 16,18 areelectrically connected to or incorporated within the electronic controlcircuit 10 for a predeterminedly short period of time, subsequent towhich, one set of the switch mechanisms 32,34,40,42 would again beactivated so as to be disposed at their OPENED position so as to servetheir redundant objective. Activating all of the switch mechanisms 32,34,40,42 to their CLOSED positions such that both of the first andsecond heater circuits or first and second heater assemblies 16,18 areelectrically connected to or incorporated within the redundant controlcircuit 10 enables the system to operate in accordance with a “boost”mode whereby, for example, a rapid heating of the hot melt adhesive hoseassembly to the predetermined desired temperature value within arelatively short period of time may be achieved. Alternatively, both ofthe first and second heater circuits or first and second heaterassemblies 16,18 may be electrically connected to or incorporated withinthe redundant control circuit 10 under low supply voltage conditions,whereas, conversely, if the supply voltage is relatively high, the useof only one of the first and second heater circuits or first and secondheater assemblies 16,18 may be necessary.

In connection with the redundant temperature sensors 24,26, it is to benoted that during normal hot melt adhesive dispensing operations orprocedures, or during normal hot melt adhesive application cycles,switch members 66,74 may be respectively moved, for example, to theirillustrated CLOSED positions at which the switch members 66,74 will berespectively electrically connected to terminals 62,70 so as toelectrically incorporate or connect the first temperature sensor 24 intothe redundant control circuit 10, whereas conversely, the switch members66,74 will effectively be disposed at their OPEN positions with respectto terminals 64,72 so as to effectively electrically disconnect orisolate the second temperature sensor 26 from the redundant controlcircuit 10. During this time, both temperature sensors 24,26 arecontinuously monitored by means of the temperature sensor voltageconverters 114,116 respectively connected across auxiliary connectionlines 52,54, and 56,58, and any time a failure or an abnormality appearsto have been detected in connection with one of the temperature sensors24,26, the temperature sensors 24,26 will effectively be tested furtherso as to determine or verify which one of the temperature sensors 24,26is in fact actually defective.

For example, both temperature sensors should exhibit or generate thesame detected voltage values. If an open or short circuit is detectedwithin a particular one of the temperature sensors 24,26, then clearlythat particular one of the temperature sensors 24,26 is defective.Accordingly, if, for example, it is determined that temperature sensor26 is in fact defective, then the switch members 66,74 are maintained attheir illustrated positions so as to maintain the temperature sensor 24electrically connected to, or incorporated within, the redundant controlcircuit 10, and to concomitantly maintain the temperature sensor 26electrically disconnected or isolated from the redundant control circuit10. On the other hand, or conversely, if, for example, it is determinedthat the temperature sensor 24 is in fact defective, then signals willbe transmitted from the microcontroller 76 to the switch mechanisms48,50, by means of signal lines 130,132, so as to cause the switchmembers 66,74 to switch positions whereby switch member 66 will now beelectrically connected to terminal 64 and switch member 74 will beelectrically connected to terminal 72. In this manner, temperaturesensor 26 will be electrically connected to, or incorporated within, theredundant control circuit 10, and temperature sensor 24 will beelectrically disconnected or isolated from the redundant control circuit10.

Continuing further, as has been noted hereinbefore, if an abnormality isdetected in connection with the operations of the temperature sensors24,26, then the temperature sensors 24,26 must be tested in order todetermine which one of the temperature sensors 24,26 is in factoperating properly and accurately sensing the temperature level of thehot melt adhesive hose assembly. Various modes or techniques for testingthe temperature sensors 24,26 are of course envisioned. For example, inaccordance with a first mode or technique for testing the temperaturesensors 24,26, if the current that is detected, by means of therespective one of the current-voltage transformers or converters 100,102which are operatively associated with the particular one of the firstand second heater circuits or first and second heater assemblies 16,18which is electrically connected to or incorporated in the redundantcontrol circuit 10, is within a valid range of values, then thetemperature level of the hot melt adhesive hose assembly, as sensed bymeans of each one of the temperature sensors 24,26, that is, thetemperature level of the hot melt adhesive hose assembly, as sensed bymeans of both of the temperature sensors 24,26, must attain apredetermined value. If this is not the case, that is, if such atemperature level is not in fact sensed or determined by each one orboth of the temperature sensors 24,26, then either the particular one ofthe temperature sensors 24,26 which is not in fact sensing the propertemperature level is not properly mounted upon or operatively connectedto the hot melt adhesive hose assembly, or the particular one of thetemperature sensors 24,26 which is not in fact sensing the propertemperature level is defective. In accordance with a second mode ortechnique for testing the temperature sensors 24,26, it is similarlynoted that the temperature level of the hot melt adhesive hose assembly,as sensed by means of each one of the temperature sensors 24,26, thatis, the temperature level of the hot melt adhesive hose assembly, assensed by means of both of the temperature sensors 24,26, must attainpredetermined values as a function of the duty cycle. In other words,the temperature levels of the hot melt adhesive hose assembly, as sensedby means of both of the temperature sensors 24,26, is directlyproportional to the duty cycle. Accordingly, if the duty cycle isincreased, an increased temperature level should be sensed, andcorrespondingly, if the duty cycle is decreased, a decreased temperaturelevel should be sensed. If a particular one of the temperature sensors24,26 is not in fact sensing the proper temperature level, in accordancewith the predetermined variations in the duty cycle, then thatparticular one of the temperature sensors 24,26 is defective.

Continuing further, a last unique feature characteristic of the presentinvention will now be described. It is to be appreciated, for example,that sometimes, despite the fact that the two temperature sensors 24,26are in fact working properly, and that they are accurately sensing thetemperature level of the hot melt adhesive hose assembly, they do not infact sense and generate the same temperature values. This may be due,for example, to the fact that the temperature sensors are being utilizedin connection with relatively large applicator heads and may bephysically located at substantially different locations within theapplicator head. Therefore, it is desirable, under such conditions, toeffectively build or configure a simulated temperature sensor which caneffectively generate output values which comprise averaged values withrespect to the temperature values actually sensed and generated by meansof the two temperature sensors 24,26. These averaged values generated bymeans of the simulated temperature sensor will then be utilized toultimately control the first or second heater circuits, or first orsecond heater assemblies, 16,18. Accordingly, in order to in factachieve this feature or objective, it is noted that the redundantcontrol circuit 10 may comprise an additional pair of single-throw,double-pole switch mechanisms 144,146, which may be similar to thesingle-throw, double-pole switch mechanisms 48,50, and a simulatedtemperature sensor-voltage converter 148 which is utilized inconjunction with the additional pair of single throw, double-pole switchmechanisms 144,146. The simulated temperature sensor-voltage converter148 is effectively built or configured from suitable hardware andsoftware incorporated within the microcontroller 76 after processingpertinent information derived from the temperature sensor-voltageconverters 114,116, and the resulting simulated temperaturesensor-voltage converter 148 can be adapted to be interactive withvarious types of adhesive supply units.

More particularly, it is noted that the additional pair of single throw,double-pole switch mechanisms 144,146, together with the simulatedtemperature sensor-voltage converter 148, effectively form an optionalor alternative sub-circuit which may effectively be electricallyconnected to or incorporated within the overall redundant controlcircuit 10, or electrically disconnected from and isolated from theoverall redundant control circuit 10. As was the case with thesingle-throw, double-pole switch mechanisms 48,50, the single-throw,double-pole switch mechanism 144 comprises a common terminal 150, a pairof alternatively selectable terminals 152,154, and a switch member 156,and in a similar manner, the single-throw, double-pole switch mechanism146 comprises a common terminal 158, a pair of alternatively selectableterminals 160,162, and a switch member 164. Still further, it is seenthat auxiliary connection lines 166,168 respectively connect thesimulated temperature sensor-voltage converter 148 to the terminals154,162 of the switch mechanisms 144, 146, and that a data communicationline 170 connects the simulated temperature sensor-voltage converter 148to a second analog-to-digital converter 172 which is incorporated withinthe microcontroller 76. In addition, it is also seen that signal lines174,176 respectively interconnect the microcontroller 76 to the switchmechanisms 144,146 so as to cause the switch members 156,164 thereof toachieve switching functions as desired.

Accordingly, it can be appreciated still further that when the switchmembers 156,164 of the switch mechanisms 144,146 are disposed at theirillustrated positions, the temperature sensors 24,26 are electricallyconnected to or incorporated within the redundant control circuit 10 ashas been previously described. On the other hand, when it is desired toeffectively electrically connect or incorporate the simulatedtemperature sensor-voltage converter 148 within the redundant controlcircuit 10, suitable signals are transmitted from the microcontroller 76so as to cause the switch members 156,164 to switch over from theirillustrated positions, at which the switch members 156,164 arerespectively connected to terminals 152,160, to their alternativepositions at which the switch members 156,164 will be respectivelyconnected to terminals 154,162. Therefore, the first and secondtemperature sensors 24,26 are effectively disconnected or isolated fromthe redundant control circuit 10 such that their generated or sensedtemperature output signals are not utilized to control the heatercircuits or heater assemblies 16,18, however, their generated or sensedtemperature output signals, as transmitted to the microcontroller 76through means of the temperature sensor-voltage converters 114,116, arenevertheless constantly utilized in conjunction with the simulatedtemperature sensor-voltage converter 148 and the temperature levelsdeveloped by means of the simulated temperature sensor-voltage converter148 in order to more accurately control the heater circuits or heaterassemblies 16, 18.

It is lastly noted, in conjunction with the simulated temperaturesensor-voltage converter 148, that even when the simulated temperaturesensor-voltage converter 148 is being employed, the redundant controlcircuit 10 still exhibits redundancy in that both of the temperaturesensors 24,26 are being used to generate their temperature level orvalue outputs, and are being used in conjunction with the simulatedtemperature sensor-voltage converter 148. In addition, if one of thetemperature sensors 24,26 proves to be defective, or fails, themicrocontroller 76 will effectively ignore the generated temperaturelevel or value outputs derived from such defective or failed temperaturesensor and will utilize the temperature level or value outputs derivedfrom the other temperature sensor. Since the active temperature sensormight be generating temperature level or value outputs which are higheror lower than the averaged temperature level or value outputs generatedby both temperature sensors 24,26, the microcontroller 76 may cause thesimulated temperature sensor-voltage converter 148 to compensateaccordingly based upon the temperature levels or value outputspreviously derived from the temperature sensors 24,26 and stored, forexample, as profiles within the EEPROM type memory unit 96.

It is lastly noted that, in conjunction with the overall redundantcontrol circuit 10 which is adapted to be operatively associated with ahot melt adhesive hose assembly, and in accordance with a unique andnovel feature characteristic of the present invention, the entireredundant control circuit 10 is adapted to be integrally connected tothe hot melt adhesive hose assembly, in a manner similar to thatdisclosed within the aforenoted U.S. patent application Ser. No.11/123,053, which is entitled HOT MELT ADHESIVE HOSE ASSEMBLY HAVINGREDUNDANT COMPONENTS, and which was filed on May 6, 2005 in the name ofDaniel D. Bourget et al., wherein the switch mechanisms were fixedlyconnected to the hot melt adhesive hose assembly, and wherein further,the hot melt adhesive hose assembly is, in turn, adapted to beoperatively connected to the adhesive supply unit (ASU) 14 through meansof the electrical connector 12. It is therefore to be appreciated andunderstood still further that in accordance with the unique and novelstructural features, principles, and teachings of the present invention,the new and improved hot melt adhesive hose assembly, which includes theheater circuits or heater resistance wires 16, 18, the temperaturesensors 24,26, the switch mechanisms 32, 34,40,42,66,74,156,164, and themicrocontroller 76, as well as the other electrical components asdisclosed within FIG. 2, effectively comprises a self-contained,stand-alone, or independent operative component that can be utilized inconjunction with any adhesive supply unit (ASU).

Thus, it may be seen that in accordance with the principles andteachings of the present invention, there has been disclosed anddescribed a redundant control circuit which is integrally incorporatedwithin or upon a hot melt adhesive hose assembly and which comprises apair of heater circuits or heater assemblies, wherein each one of thepair of heater circuits or heater assemblies is adapted to heat the hotmelt adhesive hose assembly to a predetermined temperature level, and apair of temperature sensors wherein each one of the temperature sensorsis used to sense the temperature of the hot melt adhesive hose assemblyand to provide temperature data which will be used to controlenergization of the heater circuits or heater assemblies in order tomaintain the desired temperature level. The new and improved hot meltadhesive hose assembly, which includes the heater circuits or heaterassemblies, the temperature sensors, and the switch mechanisms, as wellas the other electrical components operatively associated therewith,effectively comprises a self-contained, stand-alone, or independentoperative component that can be utilized in conjunction with anyadhesive supply unit (ASU). A first one of the heater circuits or heaterassemblies is initially electrically connected to the hot melt adhesivehose assembly electrical circuitry, and in a similar manner, a first oneof the temperature sensors is likewise electrically connected to the hotmelt adhesive hose assembly electrical circuitry. Subsequently, should afailure occur within the first one of the heater circuits or heaterassemblies, then one of the electrical switch mechanisms would beactivated so as to effectively remove the first, failed heater circuitor heater assembly from the hot melt adhesive hose assembly electricalcircuitry, and substantially simultaneously therewith, electricallyconnect the second one of the heater circuits or heater assemblies tothe hot melt adhesive hose assembly electrical circuitry. Similarswitching procedures will also be implemented in connection with thepair of temperature sensors should a failure occur within a first one ofthe temperature sensors initially incorporated within the hot meltadhesive hose assembly electrical circuitry.

Obviously, many variations and modifications of the present inventionare possible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the presentinvention may be practiced otherwise than as specifically describedherein.

1. A hot melt adhesive hose assembly having a redundant control circuitfixedly connected thereto, comprising: a power source which isoperatively associated with a hot melt adhesive supply unit (ASU); anelectrical connector mounted upon one end of a hot melt adhesive hoseassembly for electrical connection to said power source operativelyassociated with said adhesive supply unit (ASU); a pair of heaterassemblies, wherein each one of said pair of heater assemblies isadapted to be operatively associated with said hot melt adhesive hoseassembly so as to heat the hot melt adhesive material, fluidicallyconducted internally within said hot melt adhesive hose assembly, to apredetermined temperature level; first switching means for selectivelyelectrically connecting each one of said pair of heater assemblies tosaid power source by means of first power lines; a pair of temperaturesensors, wherein each one of said pair of temperature sensors is adaptedto be operatively associated with said hot melt adhesive hose assemblyso as to sense the temperature level of the hot melt adhesive materialbeing fluidically conducted internally within said hot melt adhesivehose assembly, wherein said sensed temperature levels are used foreffectively controlling the energization of each one of said pair ofheater assemblies so as to maintain the temperature level of the hotmelt adhesive material, being conducted internally within said hot meltadhesive hose assembly, at said predetermined temperature level; secondswitching means for selectively electrically connecting each one of saidpair of temperature sensors to said power source by means of secondpower lines; first means for monitoring the functionality of each one ofsaid pair of heater assemblies; second means for monitoring thefunctionality of each one of said pair of temperature sensors; and meansfor controlling said first and second switching means so as to initiallyelectrically connect a first one of said heater assemblies and a firstone of said temperature sensors to said power source, to electricallyconnect a second one of said heater assemblies to said power sourcewhile disconnecting said first one of said heater assemblies from saidpower source if said first one of said heater assemblies is determinedto be defective by said first monitoring means, and to electricallyconnect a second one of said temperature sensors to said power sourcewhile disconnecting said first one of said temperature sensors from saidpower source if said first one of said temperature sensors is determinedto be defective by said second monitoring means, said electricalconnector, said pair of heater assemblies, said first switching means,said pair of temperature sensors, said second switching means, saidfirst means for monitoring the functionality of each one of said pair ofheater assemblies, said second means for monitoring the functionality ofeach one of said pair of temperature sensors, and said means forcontrolling said first and second switching means being fixedlyconnected to said hot melt adhesive hose assembly such that said hotmelt adhesive hose assembly, including said electrical connector, saidpair of heater assemblies, said first switching means, said pair oftemperature sensors, said second switching means, said first means formonitoring the functionality of each one of said pair of heaterassemblies, said second means for monitoring the functionality of eachone of said pair of temperature sensors, and said means for controllingsaid first and second switching means, effectively comprises aself-contained, stand-alone, independent operative component that can beutilized in conjunction with any adhesive supply unit (ASU).
 2. Theredundant control circuit as set forth in claim 1, wherein: said meansfor monitoring each one of said pair of heater assemblies comprises apair of current-voltage converters electrically connected to said firstpower lines.
 3. The redundant control circuit as set forth in claim 1,wherein: said means for monitoring each one of said pair of heaterassemblies comprises a voltage detector electrically connected acrosssaid first power lines.
 4. The redundant control circuit as set forth inclaim 1, wherein: said means for monitoring each one of said pair oftemperature sensors comprises a pair of temperature sensor-voltageconverters electrically connected across said second power lines.
 5. Theredundant control circuit as set forth in claim 1, wherein: said meansfor controlling said first and second switching means comprises amicrocontroller.
 6. The redundant control circuit as set forth in claim5, further comprising: memory means, operatively associated with saidmicrocontroller, for storing operational profiles characteristic of saidredundant control circuit, said pair of heater assemblies, and said pairof temperature sensors.
 7. The redundant control circuit as set forth inclaim 1, further comprising: a simulated temperature sensor configuredby said microcontroller as a function of temperature data received fromsaid pair of temperature sensors; and third switching means forelectrically connecting said simulated temperature sensor to said powersource by means of said second power lines, while electricallydisconnecting said pair of temperature sensors from said second powerlines.
 8. A hose assembly for fluidically conveying a heated fluid andhaving redundant control circuit fixedly connected thereto, comprising:a power source which is operatively associated with a heated fluidsupply unit; an electrical connector mounted upon one end of a hoseassembly for electrical connection to said power source; at least onepair of electrical components disposed within a redundant controlcircuit; switching means for selectively electrically connecting eachone of said at least one pair of electrical components to said powersource by means of power lines; means for monitoring the functionalityof each one of said at least one pair of electrical components; andmeans for controlling said switching means so as to initiallyelectrically connect a first one of said at least one pair of electricalcomponents to said power source, and to electrically connect a secondone of said at least one pair of electrical components to said powersource while disconnecting said first one of said at least one pair ofelectrical components from said power source if said first one of saidat least one pair of electrical components is determined to be defectiveby said monitoring means, said electrical connector, said at least onepair of electrical components, said switching means, said means formonitoring the functionality of each one of said at least one pair ofelectrical components, and said means for controlling said switchingmeans being fixedly connected to said hose assembly such that said hoseassembly, including said said electrical connector, said at least onepair of electrical components, said switching means, said means formonitoring the functionality of each one of said at least one pair ofelectrical components, and said means for controlling said switchingmeans, effectively comprises a self-contained, stand-alone, independentoperative component that can be utilized in conjunction with any heatedfluid supply unit.
 9. The redundant control circuit as set forth inclaim 8, wherein: said electrical system comprises an electrical systemoperatively associated with a hot melt adhesive hose assembly; and saidat least one pair of electrical components comprises a pair of heaterassemblies and a pair of temperature sensors.
 10. The redundant controlcircuit as set forth in claim 9, wherein: said means for monitoring eachone of said pair of heater assemblies comprises a pair ofcurrent-voltage converters electrically connected to first power lineselectrically connecting said pair of heater assemblies to said powersource.
 11. The redundant control circuit as set forth in claim 10,wherein: said means for monitoring each one of said pair of heaterassemblies comprises a voltage detector electrically connected acrosssaid first power lines.
 12. The redundant control circuit as set forthin claim 9, wherein: said means for monitoring each one of said pair oftemperature sensors comprises a pair of temperature sensor-voltageconverters electrically connected across second power lines electricallyconnecting said pair of temperature sensors to said power source. 13.The redundant control circuit as set forth in claim 9, wherein: saidmeans for controlling said switching means comprises a microcontroller.14. The redundant control circuit as set forth in claim 13, furthercomprising: memory means, operatively associated with saidmicrocontroller, for storing operational profiles characteristic of saidredundant control circuit, said pair of heater assemblies, and said pairof temperature sensors.
 15. The redundant control circuit as set forthin claim 13, further comprising: a simulated temperature sensorconfigured by said microcontroller as a function of temperature datareceived from said pair of temperature sensors; and third switchingmeans for electrically connecting said simulated temperature sensor tosaid power source by means of said second power lines, whileelectrically disconnecting said pair of temperature sensors from saidsecond power lines.